Heavy minerals of the Barakar Formation,Talchir Gondwana Basin,Orissa

Heavy mineral analysis has been carried out in the Barakar Formation of the Talchir Gondwana Bbasin, Orissa. The characteristic heavy minerals are garnet, zircon, tourmaline, rutile, biotite, chlorite, pyroxenes, hornblende, staurolite, sillimanite, apatite, epidote, sphene, spinel and siderite including opaques and leucoxene. These heavy minerals are divisible into four groups on the basis of principal component analysis and suggest derivation of Barakar sediments from pegmatite, acid and basic igneous as well as low- and high-rank metamorphic rocks lying to the south of the Talchir Gondwana Basin. Though the heavy mineral suites of all the sandstone samples are by and large similar, differences have been noticed in the frequencies of many heavy minerals in vertical succession. Cyclic nature and vertical fluctuation of heavy mineral frequencies can be ascribed to variation of the relief of the source area, sudden release of some of the minerals in the source region and/or existence of favourable geochemical condition to escape partial dissolution.